I upgraded to 3.5.1 and found all my logins stopped working.
The site is OK from the user's side. But it is impossible to get to the Admin Panel. The login box will correctly reset a password, but the new password still only leads to a shaky login box :(
I have re-installed everything, including V3.4 but still the problem continues. I have disabled all plugins & themes but no conflicts can be found.
I have reinstalled a new WP-3.5.1 from scratch and it works on test -until I install all any existing SQL backup files; then the login stops functioning again.
Any thoughts on a solution? I'd like to update the site....
Regards and thanks, Angus